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Although there has been extensive development and exploration of small-scale robots, the technological challenges associated with their complicated and high-cost fabrication processes remain unresolved. Here, we report a one-step, bi-material, high-resolution three-dimensional (3D) printing method for the fabrication of multi-stimuli-responsive microactuators. This method exploits a two-phase femtoliter ink meniscus formed on a double-barreled theta micropipette to continuously print a freestanding bilayer microstructure, which undergoes an asymmetric volume change upon the adsorption or desorption of water. We show that the 3D-printed bilayer microstructures exhibit reversible, reproducible actuation in ambient humidity or under illumination with infrared light. Our 3D printing approach can assemble bilayer segments for programming microscale actuation, as demonstrated by proof-of-concept experiments. We expect that this method will serve as the basis for flexible, programmable, one-step routes for the assembly of small-scale intelligent actuators.

Hybrid perovskites are emerging as a promising, high-performance luminescent material; however, the technological challenges associated with generating high-resolution, free-form perovskite structures remain unresolved, limiting innovation in optoelectronic devices. Here, we report nanoscale three-dimensional (3D) printing of colored perovskite pixels with programmed dimensions, placements, and emission characteristics. Notably, a meniscus comprising femtoliters of ink is used to guide a highly confined, out-of-plane crystallization process, which generates 3D red, green, and blue (RGB) perovskite nanopixels with ultrahigh integration density. We show that the 3D form of these nanopixels enhances their emission brightness without sacrificing their lateral resolution, thereby enabling the fabrication of high-resolution displays with improved brightness. Furthermore, 3D pixels can store and encode additional information into their vertical heights, providing multilevel security against counterfeiting. The proof-of-concept experiments demonstrate the potential of 3D printing to become a platform for the manufacture of smart, high-performance photonic devices without design restrictions.

Designing a run-length-limited (RLL) code for a visible light communication (VLC) system requires consideration of several performance factors including hardware overhead, transmission efficiency, and direct current (DC) balance. This paper proposes a novel RLL code called bit-shuffle block codes for high-rate multiple-input multiple-output (MIMO)-VLC systems that can offer excellent constant illumination and transmission efficiency with extensively-optimized hardware resources. Due to the structure of the Omega network, the proposed bit-shuffle block coding method can increase transmission efficiency and significantly reduce hardware overhead. In addition, it can generate codewords dynamically, which guarantees DC balance with multiple LEDs to serve the dual purpose of illumination and communication. Experimental results confirm that the proposed bit-shuffle block coding demonstrate excellent performance in resource optimization, and can be a viable solution for MIMO-VLC applications that can send large volumes data with limited hardware resources.

Calcific tendinitis is the leading cause of shoulder pain. Among patients with calcific tendinitis, 2.7%–20% are asymptomatic, and 35%–45% of patients whose calcific deposits are inadvertently discovered develop shoulder pain. If symptoms are present, complications such as decreased range of motion of the shoulder joint should be minimized while managing pain. Patients with acute calcific tendinitis respond well to conservative treatment and rarely require surgery. In contrast, patients with chronic calcific tendinitis often do not respond to conservative treatment and do require surgery. Clinical improvement takes time, even after surgical treatment. This review article summarizes the processes related to the diagnosis and treatment of calcific tendinitis with the aim of helping clinicians choose appropriate treatment options for their patients.

Time ranges of revision rotator cuff surgeries after arthroscopic repair are highly variable. However, the cause and clinical relevance of the different timings of revision surgeries have not been analyzed. The purpose of this study was to evaluate the clinical manifestations of patients who required revision surgeries at early and late periods after failed arthroscopic rotator cuff repair, and to identify clinical and radiological differences related to the timing of revision surgery. Sixty patients who underwent revision surgery due to symptomatic failed rotator cuff repair after arthroscopic repair were included. Patients were divided into two groups: patients who underwent revision surgeries within 1 year postoperatively (21 patients, group I) and patients who underwent revision surgeries more than 1 year postoperatively (39 patients, group II). Clinical and radiological characteristics were compared between the two groups before primary and revision surgery. VAS for pain (5.9 ± 1.9 in group I, 3.9 ± 1.4 in group II, P

Magnetic graphene composite comprising graphene sheets decorated with magnetite nanoparticles (NPs) is an important material with numerous successful and potential applications in electronics, chemistry, physics, and bio-medicine. The further use of this material relies on the development of an appropriate patterning method for the production of two-dimensional (2D) and three-dimensional (3D) magnetic graphene composite objects. This study presents a simple and effective strategy to fabricate 2D and 3D micropatterns of Fe3O4 functionalized graphene-polymer (FGP) nanocomposite using extrusion-based 3D printing with a highly loaded FGP nanocomposite ink. The ink consisted of Fe3O4 nanoparticles (NPs), graphene microflakes (GMFs), and hydroxypropyl cellulose (HPC), and was stable and suitable for 3D printing of FGP objects. Various FGP 3D microarchitectures, including a grid, honeycomb, pyramid, and square, were successfully printed using the layer-by-layer (LbL) printing approach. The printed objects exhibited a conductivity of ∼580 S m−1 and magnetic property of 15.8 emu g−1. Successful demonstrations of electronic devices such as a magnet-guided car, a magnetic switch, and a 3D grid for electromagnetic interference (EMI) shielding are also described herein. This 3D printing approach was effective for the 2D and 3D patterning of functional nanocomposites and shows promise for advanced printed electronic applications.

Photoelectrochemical (PEC) water splitting is an alternative to fossil fuel combustion involving the generation of renewable hydrogen without environmental pollution or greenhouse gas emissions. Cuprous oxide (Cu2O) is a promising semiconducting material for the simple reduction of hydrogen from water, in which the conduction band edge is slightly negative compared to the water reduction potential. However, the solar-to-hydrogen conversion efficiency of Cu2O is lower than the theoretical value due to a short carrier-diffusion length under the effective light absorption depth. Thus, increasing light absorption in the electrode–electrolyte interfacial layer of a Cu2O photoelectrode can enhance PEC performance. In this study, a Cu2O 3D photoelectrode comprised of pyramid arrays was fabricated using a two-step method involving direct-ink-writing of graphene structures. This was followed by the electrodeposition of a Cu current-collecting layer and a p–n homojunction Cu2O photocatalyst layer onto the printed structures. The performance for PEC water splitting was enhanced by increasing the total light absorption area (Aa) of the photoelectrode via controlling the electrode topography. The 3D photoelectrode (Aa = 3.2 cm2) printed on the substrate area of 1.0 cm2 exhibited a photocurrent (Iph) of −3.01 mA at 0.02 V (vs. RHE), which is approximately three times higher than that of a planar photoelectrode with an Aa = 1.0 cm2 (Iph = −0.91 mA). Our 3D printing strategy provides a flexible approach for the design and the fabrication of highly efficient PEC photoelectrodes.

Interscalene brachial plexus block (ISB) is one of the most commonly used regional blocks in relieving postoperative pain after arthroscopic rotator cuff repair. Dexmedetomidine (DEX) is an alpha 2 agonist that can enhance the effect of regional blocks. The aim of this study was to compare the effects of DEX combined with ISB with ISB alone on postoperative pain, satisfaction, and pain-related cytokines within the first 48 h after arthroscopic rotator cuff repair. Fifty patients with rotator cuff tears who had undergone arthroscopic rotator cuff repair were enrolled in this single center, double-blinded randomized controlled trial study. Twenty-five patients were randomly allocated to group 1 and received ultrasound-guided ISB using a mixture of 1 ml (100 μg) of DEX and 8 ml of 0.75% ropivacaine preemptively. The other 25 patients were allocated to group 2 and underwent ultrasound-guided ISB alone using a mixture of 1 ml of normal saline and 8 ml of ropivacaine. The visual analog scale (VAS) for pain and patient satisfaction (SAT) scores were checked within 48 h postoperatively. The plasma interleukin (IL)-6, -8, -1β, cortisol, and substance P levels were also measured within 48 h, postoperatively. Group 1 showed a significantly lower mean VAS score and a significantly higher mean SAT score than group 2 at 1, 3, 6, 12, and 18 h postoperatively. Compared with group 2, group 1 showed a significantly lower mean plasma IL-6 level at 1, 6, 12, and 48 h postoperatively and a significantly lower mean IL-8 level at 1, 6, 12, 24, and 48 h postoperatively. The mean timing of rebound pain in group 1 was significantly later than that in group 2 (12.7 h > 9.4 h, p = 0.006). Ultrasound-guided ISB with DEX in arthroscopic rotator cuff repair led to a significantly lower mean VAS score and a significantly higher mean SAT score within 48 h postoperatively than ISB alone. In addition, ISB with DEX showed lower mean plasma IL-6 and IL-8 levels than ISB alone within 48 h postoperatively, with delayed rebound pain. I. 2013-112, ClinicalTrials.gov Identifier: NCT02766556.

As object recognition technology has developed recently, various technologies have been applied to autonomous vehicles, robots, and industrial facilities. However, the benefits of these technologies are not reaching the visually impaired, who need it the most. In this paper, we proposed an object detection system for the blind using deep learning technologies. We use voice recognition technology in order to know what objects a blind person wants, and then to find the objects via object recognition. Furthermore, a voice guidance technique is used to inform sightimpaired persons as to the location of objects. The object recognition deep learning model utilizes the Single Shot Multibox Detector (SSD) neural network architecture, and voice recognition is designed through speech-to-text (STT) technology. In addition, a voice announcement is synthesized using text-to-speech (TTS) to make it easier for the blind to get information about objects. The control system is based on the Arduino microprocessor. As a result, we implement an efficient object-detection system that helps the blind find objects in a specific space without help from others, and the system is analyzed through experiments to verify performance.

Three-dimensional (3D) printing is a next-generation free-form manufacturing technology for structural electronics. The realization of structural electronic devices necessitates the direct integration of electronic circuits into 3D objects. However, creating highly conductive, high-resolution patterns in 3D remains a major challenge. Here, we report on a metallic 3D printing method that incorporates electroless deposition (ELD) into the direct ink writing method. Our approach consists of two steps: (1) direct ink writing of catalyst microstructures with a functional catalyst ink containing Ag ions and (2) ELD of Cu onto the printed catalyst structures. High-quality, stable Cu 3D printing is achieved through the design of the Ag catalyst ink; hydroxypropyl cellulose is added as both a rheological modifier (printing) and dissolution inhibitor (ELD). As a result, various two-dimensional (2D) and 3D Cu micro circuitries with high conductivity (∼65% of bulk) can be directly integrated onto 3D plastic substrates without the need for high-temperature annealing. A hybrid strategy that combines ELD-assisted 3D printing and conventional fused deposition modeling enables full fabrication of structural electronic devices. This 3D printing strategy can be a low-cost and facile method for obtaining highly conductive metallic 2D and 3D microstructures in structural electronics.

PURPOSE The purpose of this study is to report structural integrity and clinical outcomes of superior capsular reconstruction (SCR) using a 4- to 5-mm acellular dermal allograft combined with augmentation of the remaining rotator cuff to the graft. METHODS We prospectively recruited 21 patients with symptomatic irreparable rotator cuff tear who required SCR. At least 6 months after the SCR, we evaluated each patient's graft healing by magnetic resonance imaging (MRI). We also assessed the range of motion (ROM), strength for forward flexion and external rotation, visual analog scale for pain (PVAS), American Shoulder and Elbow Surgeon (ASES) score, and Constant score. At minimum of 1 year after the surgery, we evaluated the number of patients with minimal clinically important differences (MCIDs) for each score to compare patients with healed and unhealed grafts. RESULTS Postoperative MRI showed the grafts intact in 14 patients (66.7%). Among 7 patients with unhealed grafts, tears were observed in 3 patients (42.9%) on the glenoid side, 3 (42.9%) on the humeral side, and 1 (14.3%) on both sides. PVAS, ASES score, and the Constant score improved after surgery (4.0 to 0.7 for PVAS [P < .001], 55.5 to 87.0 for ASES score [P < .001], and 56.0 to 65.9 for Constant score [P = .007]). However, there were no differences in postoperative ROM and muscle strength compared to preoperative measurements. MCIDs were reached in 90.5% of patients (n = 19) for the PVAS and in 71.4% of patients (n = 15) for the ASES score. Only 33.3% of patients (n = 7) obtained MCIDs for the Constant score, and none of the patients with a graft tear obtained MCIDs in the Constant score (P = .047). CONCLUSION The graft complete healing rate was 66.7%, although pain relief and functional improvement were satisfactory regardless of graft structural integrity. However, muscle strength recovery was not optimal until 1 year after surgery. LEVEL OF EVIDENCE Level IV; case series.

The objective of this study was to investigate the importance of multiple county-level features in the trajectory of COVID-19. We examined feature importance across 2787 counties in the United States using data-driven machine learning models. Existing mathematical models of disease spread usually focused on the case prediction with different infection rates without incorporating multiple heterogeneous features that could impact the spatial and temporal trajectory of COVID-19. Recognizing this, we trained a data-driven model using 23 features representing six key influencing factors affecting the pandemic spread: social demographics of counties, population activities, mobility within the counties, movement across counties, disease attributes, and social network structure. Also, we categorized counties into multiple groups according to their population densities, and we divided the trajectory of COVID-19 into three stages: the outbreak stage, the social distancing stage, and the reopening stage. The study aimed to answer two research questions: (1) The extent to which the importance of heterogeneous features evolved at different stages; (2) The extent to which the importance of heterogeneous features varied across counties with different characteristics. We fitted a set of random forest models to determine weekly feature importance. The results showed that: (1) Social demographic features, such as gross domestic product, population density, and minority status maintained high-importance features throughout stages of COVID-19 across 2787 studied counties; (2) Within-county mobility features had the highest importance in counties with higher population densities; (3) The feature reflecting the social network structure (Facebook, social connectedness index), had higher importance for counties with higher population densities. The results showed that the data-driven machine learning models could provide important insights to inform policymakers regarding feature importance for counties with various population densities and at different stages of a pandemic life cycle.

(1) Background: Ingrown toenail is a common disorder of the toe that induces severe toe pain and limits daily activities. The Winograd method, the most widely used operative modality for ingrown toenails, has been modified over years to include wedge resection of the nail fold and complete ablation of the germinal matrix. We evaluated the outcomes of original Winograd procedure without wedge resection with electrocautery-aided matrixectomy. (2) Methods: We retrospectively analyzed the outcomes of patients who underwent surgery for ingrown toenails at a university hospital for two years from November 2015 to October 2017. Surgery was performed in 76 feet with a mean operation time of 9.34 min. (3) Results: The minimal interval from surgery to return to regular activities was 13.26 (range 7 to 22) days. Recurrence and postoperative wound infections were found in 3 (3.95%) and 2 (2.63%) patients, respectively. Evaluation of patient satisfaction at one-year follow-up showed that 40 (52.63%) patients were very satisfied, 33 (43.42%) were satisfied, 3 (3.95%) were dissatisfied, and none of them were very dissatisfied. The average follow-up duration was 14.66 (range 12 to 25) months. (4) Conclusions: Therefore, it is believed that this less-invasive and simple procedure could be easily performed by clinicians, with satisfactory patient outcomes.

Repair of a retracted anterior L-shaped rotator cuff tear is challenging because of the lack of mobilization of the torn tendon and destruction of the rotator cable. Restoring the anterior rotator cable decreases gap formation of the repaired tendon, leading to maintenance of the repair integrity of the anterior supraspinatus tendon. This Technical Note introduces the surgical technique of anterior cable reconstruction using the proximal biceps tendon for a retracted anterior L-shaped rotator cuff tear.

To evaluate the correlation between cutting-through at the greater tuberosity (GT) in arthroscopic suture-bridge rotator cuff repair and the bone mineral density (BMD) of the lumbar spine, hip, and ipsilateral GT of the proximal humerus and to evaluate factors and clinical outcomes related to cutting-through.This study prospectively enrolled patients who underwent arthroscopic knotted suture-bridge rotator cuff repair for full-thickness rotator cuff tears between June 2014 and October 2015 and who had undergone dual-energy X-ray absorptiometry cans within 1 month before surgery with a minimum 2-year follow-up. Cutting-through was defined as the occurrence of cortical breakage of the GT just medial to the lateral knotless anchor hole due to the tension of the sutures from the medial anchor, and it was assessed. Clinical and radiologic data were analyzed. Univariate and regression analyses were performed to evaluate factors related to cutting-through.A total of 78 patients were analyzed. Patients were divided into 2 groups: patients who had cutting-through (46, group I) and patients who did not (32, group II). In an analysis of lumbar spine, hip, and GT BMD, GT BMD was the most effective for predicting cutting-through (area under the receiver operating characteristic curve = 0.94, 95% confidence interval 0.89-0.99). GT BMD (P.001) and tear size (P = .004) were independent factors for cutting-through. Although a significant difference was found between the 2 groups in terms of age, sex, lumbar spine and hip BMD, fatty infiltration of the supraspinatus and infraspinatus, and atrophy of the supraspinatus, these variables were not independent factors. Clinical and structural outcomes showed no significant difference between the 2 groups, and anchor failure was not identified intraoperatively.GT BMD and rotator cuff tear size are independent factors associated with cutting-through at the GT. A dual-energy X-ray absorptiometry scan of the proximal humerus is useful for predicting bone quality before arthroscopic suture-bridge rotator cuff repair.Level II, Prospective cohort study.

The pixel is the minimum unit used to represent or record information in photonic devices. The size of the pixel determines the density of the integrated information, such as the resolution of displays or cameras. Most methods used to produce display pixels are based on two-dimensional patterning of light-emitting materials. However, the brightness of the pixels is limited when they are miniaturized to nanoscale dimensions owing to their limited volume. Herein, we demonstrate the production of three-dimensional (3D) pixels with nanoscale dimensions based on the 3D printing of quantum dots embedded in polymer nanowires. In particular, a femtoliter meniscus was used to guide the solidification of liquid inks to form vertically freestanding nanopillar structures. Based on the 3D layout, we show high-density integration of color pixels, with a lateral dimension of 620 nm and a pitch of 3 μm for each of the red, green, and blue colors. The 3D structure enabled a 2-fold increase in brightness without significant effects on the spatial resolution of the pixels. In addition, we demonstrate individual control of the brightness based on a simple adjustment of the height of the 3D pixels. This method can be used to achieve super-high-resolution display devices and various photonic applications across a range of disciplines.

Many emerging applications in microscale engineering rely on the fabrication of three-dimensional architectures in inorganic materials. Small-scale additive manufacturing (AM) aspires to provide flexible and facile access to these geometries. Yet, the synthesis of device-grade inorganic materials is still a key challenge towards the implementation of AM in microfabrication. Here, we present a comprehensive overview of the microstructural and mechanical properties of metals fabricated by most state-of-the-art AM methods that offer a spatial resolution $\leq$10$\mu$m. Standardized sets of samples were studied by cross-sectional electron microscopy, nanoindentation and microcompression. We show that current microscale AM techniques synthesize metals with a wide range of microstructures and elastic and plastic properties, including materials of dense and crystalline microstructure with excellent mechanical properties that compare well to those of thin-film nanocrystalline materials. The large variation in materials performance can be related to the individual microstructure, which in turn is coupled to the various physico-chemical principles exploited by the different printing methods. The study provides practical guidelines for users of small-scale additive methods and establishes a baseline for the future optimization of the properties of printed metallic objects $-$ a significant step towards the potential establishment of AM techniques in microfabrication.

Purpose: The purpose of this study is to evaluate the incidence and treatment of recurrent hemarthrosis after total knee replacement (TKR). Materials and Methods: Among a total of 5,510 patients who underwent TKR from March 2000 to October 2016, patients who had two or more bleeding 2 weeks after surgery were studied. Conservative treatments were performed for all cases with symptoms. In patients who did not respond to conservative treatment several times, embolization was performed. We retrospectively evaluated the postoperative bleeding time, bleeding frequency, treatment method, and outcome. Results: Seventeen (0.3%) of the 5,510 patients developed recurrent hemarthrosis. Bleeding occurred at an average of 2 years 3 months after the operation. Joint aspiration was performed 3.5 times (range, 2 to 10 times) on average, and 14 cases (82.3%) were treated with conservative treatment. In 3 patients with severe bleeding and hemorrhage, embolization was performed. Conclusions: Recurrent hemarthrosis after TKR is a rare disease with a low incidence of 0.3% and usually could be treated by conservative treatment. If recurrences occur repeatedly, embolization through angiography or surgical treatment may be considered, but the results are not satisfactory and careful selection of treatment modalities is warranted.

Background The posterior malleolar fragment (PMF) of an ankle fracture can have various shapes depending on the injury mechanism. The purpose of this study was to evaluate the morphological characteristics of the PMF according to the ankle fracture pattern described in the Lauge-Hansen classification by using computed tomography (CT) images. Methods We retrospectively analyzed CT data of 107 patients (107 ankles) who underwent surgery for trimalleolar fracture from January 2012 to December 2014. The patients were divided into two groups: 76 ankles in the supination-external rotation (SER) stage IV group and 31 ankles in the pronation-external rotation (PER) stage IV group. The PMF type of the two groups was assessed using the Haraguchi and Jan Bartonicek classification. The cross angle (α), fragment length ratio (FLR), fragment area ratio (FAR), sagittal angle (θ), and fragment height (FH) were measured to assess the morphological characteristics of the PMF. Results The PMF in the SER group mainly had a posterolateral shape, whereas that in the PER group mainly had a posteromedial two-part shape or a large posterolateral triangular shape (P = 0.02). The average cross angle was not significantly different between the two groups (SER group = 19.4°, PER group = 17.6°). The mean FLR and FH were significantly larger in the PER group than in the SER group (P = 0.024, P = 0.006). The mean fragment sagittal angle in the PER group was significantly smaller than that in the SER group (P = 0.017). Conclusions With regard to the articular involvement, volume, and vertical nature, the SER-type fracture tends to have a smaller fragment due to the rotational force, whereas the PER-type fracture tends to have a larger fragment due to the combination of rotational and axial forces.

Although three-dimensional (3D) printing has recently emerged as a technology to potentially bring about the next industrial revolution, the limited selection of usable materials restricts its use to simple prototyping. In particular, metallic 3D printing with submicrometer spatial resolution is essential for the realization of 3D-printed electronics. Herein, a meniscus-guided 3D printing method that exploits a low-viscosity (∼7 mPa·s) silver nanoparticle (AgNP) ink meniscus with Newtonian fluid characteristics (which is compatible with conventional inkjet printers) to fabricate 3D silver microarchitectures is reported. Poly(acrylic acid)-capped AgNP ink that exhibits a continuous ink flow through a confined nozzle without aggregation is designed in this study. Guiding the ink meniscus with controlled direction and speed enables both vertical pulling and layer-by-layer processing, resulting in the creation of 3D microobjects with designed shapes other than those for simple wiring. Various highly conductive (10

To evaluate the clinical characteristics of patients with symptomatic failed rotator cuff repair who required revision surgeries and to identify clinical and radiologic factors related to the need for revision surgery.Ninety-eight patients who were diagnosed with rotator cuff retear within 2 years after primary arthroscopic surgery were included. Patients were divided into 2 groups: patients who underwent revision surgery within 2 years postoperatively (44 patients, group I) and patients who did not require additional treatment due to minimal discomfort during the same period (54 patients, group II). Demographic and radiographic factors related to cuff healing were analyzed. Univariate and multivariate analyses were performed to evaluate factors related to revision surgery.Group I showed significantly inferior clinical outcomes at the time of revision compared to group II (American Shoulder and Elbow Surgeons score; 54.0 ± 12.1 vs 86.5 ± 12.2, Constant score; 65.2 ± 10.8 vs 84.0 ± 11.4, P.001). Total cholesterol level (210.2 ± 40.0 vs 189.7 ± 39.1, P = .012), low-density lipoprotein level (130.7 ± 28.7 vs 115.5 ± 26.9, P = .008), and fatty infiltration of the infraspinatus (20.5% vs 3.7%, P = .011) were significantly greater in group I than in group II. On postoperative magnetic resonance imaging, retear of the infraspinatus tendon occurred significantly more frequently in group I (81.8%) than in group II (37.0%, P.001). In group I, relative changes in anteroposterior (AP) (19.2 ± 37.8) and mediolateral retear size (29.6 ± 90.7) were significantly greater than in group II (AP; -39.5 ± 19.2, mediolateral; -29.2 ± 26.8, P.001). Relative change in AP retear size was the most powerful independent predictor of symptomatic failed rotator cuff repair (odds ratio 1.19, confidence interval 1.08-1.31, P.001).Preoperative serum total cholesterol level, low-density lipoprotein levels, and fatty infiltration of the infraspinatus were significantly related to symptomatic failed rotator cuff repair. Relative change in AP retear size was the most powerful independent predictor of symptomatic failed rotator cuff repair.Level III, Case-control study.

Silver (Ag) nanoparticle-based inks are frequently used in printed electronics to form conductive patterns, but often require high-temperature sintering to achieve the optimum electrical conductivity, hindering their use in substrates with poor heat resistance. Herein, a three-dimensional (3D) printing strategy to produce highly conductive Ag 3D architectures that can be sintered at low temperatures is reported. This strategy is based on the additive deposition of Ag nanoparticles and microflakes via extrusion-based 3D printing with the Ag ink that involves poly(acrylic acid) (PAA)-stabilized Ag nanoparticles, Ag microflakes, and NaCl - a destabilizing agent. The designed Ag inks are stable and suitable for ink-extrusion 3D printing. In chemical sintering, Cl- can detach PAA from the Ag nanoparticle surface, enabling nanoparticle coalescence and sintering. An elevated annealing temperature induces increased NaCl density in the printed patterns and accelerates the surface and grain boundary diffusion of Ag atoms, contributing to enhance chemical sintering. On annealing at ∼110 °C for 30 min, the printed structures exhibited an electrical conductivity of ∼9.72 × 104 S cm-1, which is ∼15.6% of that of bulk Ag. Complicated Ag architectures with diverse shapes were successfully fabricated on polymeric substrates. Several structural electronic applications were demonstrated by hybrid 3D printing combining our extrusion-based 3D printing and conventional fused deposition modeling (FDM).

The 21st century, which we live in today, is rapidly changing based on the fourth industrial revolution and information and communication technology. According to change, existing urban models are emerging as smart cities. Smart City is a sustainable city that improves urban functions of various elements by applying information and communication convergence technology and environment friendly technology to urban space and solves urban problems that are occurring now. Energy, a core element of the city, enables efficient energy management of energy systems through an Internet of Things-based platform. The Internet of Things is a technology that sends and receives data by attaching sensors to various objects through a network. The goal is to use resources efficiently as the Internet of Things is spread and various industries are applied. This paper is a prediction study based on machine learning algorithms for efficient use of energy infrastructure in the Smart City. The proposed system builds the optimal Smart City by estimating energy efficiency of the Smart City and improving resource utilization.

Moving printed electronics to three dimensions essentially requires advanced additive manufacturing techniques yielding multifunctionality materials and high spatial resolution. Here, we report the meniscus-guided 3D printing of highly conductive multiwall carbon nanotube (MWNT) microarchitectures that exploit rapid solidification of a fluid ink meniscus formed by pulling a micronozzle. To achieve high-quality printing with continuous ink flow through a confined nozzle geometry, that is, without agglomeration and nozzle clogging, we design a polyvinylpyrrolidone-wrapped MWNT ink with uniform dispersion and appropriate rheological properties. The developed technique can produce various desired 3D microstructures, with a high MWNT concentration of up to 75 wt % being obtained via post-thermal treatment. Successful demonstrations of electronic components such as sensing transducers, emitters, and radio frequency inductors are also described herein. We expect that the technique presented in this study will facilitate selection of diverse materials in 3D printing and enhance the freedom of integration for advanced conceptual devices.

3D printing of metallic microarchitectures with controlled internal structures is realized at room temperature in ambient air conditions by the manipulation of metal ion concentration and pulsed electric potentials in the electrolyte meniscus during the meniscus-guided electrodeposition. Precise control of the printing nozzle enables the drawing of complex 3D microarchitectures with well-defined geometries and positions.

As competing with the established silicon technology, organic-inorganic metal halide perovskites are continually gaining ground in optoelectronics due to their excellent material properties and low-cost production. The ability to have control over their shape, as well as composition and crystallinity, is indispensable for practical materialization. Many sophisticated nanofabrication methods have been devised to shape perovskites; however, they are still limited to in-plane, low-aspect-ratio, and simple forms. This is in stark contrast with the demands of modern optoelectronics with freeform circuitry and high integration density. Here, a nanoprecision 3D printing is developed for organic-inorganic metal halide perovskites. The method is based on guiding evaporation-induced perovskite crystallization in mid-air using a femtoliter ink meniscus formed on a nanopipette, resulting in freestanding 3D perovskite nanostructures with a preferred crystal orientation. Stretching the ink meniscus with a pulling process enables on-demand control of the nanostructure's diameter and hollowness, leading to an unprecedented tubular-solid transition. With varying the pulling direction, a layer-by-layer stacking of perovskite nanostructures is successfully demonstrated with programmed shapes and positions, a primary step for additive manufacturing. It is expected that the method has the potential to create freeform perovskite nanostructures for customized optoelectronics.

Rationale The operative procedure for Achilles tendon rupture is relatively simple, but venous thromboembolism is serious complication with a high incidence after Achilles tendon rupture. However, the guideline for thromboprophylaxis in Achilles tendon rupture is unclear. Patient concerns The patient was 32-year-old male and underwent Achilles tendon open repair surgery. He was healthy and there are no abnormal findings other than Achilles tendon rupture. At 3 weeks after operation, the episode of loss of consciousness with convulsive movement occurred. The next day, suddenly cardiac arrest occurred. Diagnoses Extensive pulmonary thromboembolism in both pulmonary arteries was identified in chest computed tomography and thrombus was also identified at the left popliteal vein on ultrasonography. Intervention Anticoagulant therapy with heparin sodium was performed to manage the pulmonary thromboembolism. Outcomes Brain swelling after ischemic brain damage, acute kidney injury, and pneumonia gradually occurred and aggravated. His condition became worse and he died about 2 weeks after the cardiac arrest episode. Lessons Although the incidence of venous thromboembolism in Achilles tendon rupture is higher than that in lower leg injury patients, guideline for thromboprophylaxis is unclear. We suggest that thromboprophylaxis for Achilles tendon rupture should be considered and appropriate guidelines should be established.

Based on field induced atomic migration, one of the cycling endurance failure mechanisms in phase change memories, we propose an electrical treatment method to reduce atomic migration. The electric treatment is performed by applying compensation voltage after set or reset voltage applications, and we have a substantial enhancement of cycling endurance characteristics. The polarity of the compensation voltage is negative with respect to the programming voltages. To further investigate the effect of the electrical treatment, we introduced a parameter named melting voltage, which steadily increases as the number of set/reset cycling increases. This observation is consistent with the increase of resistance at the reset voltage, which supports void formation in the active region of Ge2Sb2Te5 with cycling stress.

IMT-Advanced system proposed by ITU-R for next generation mobile communications has the technical requirements of the performances of an improved broadcast, a multicast and a VoIP by supporting the transmission rates up to 100 Mbps for high mobility and 1 Gbps for low mobility. LTE-Advanced system is one of the leading candidates of IMT-Advanced systems and many telecommunications industries will introduce LTE-Advanced system widely. Therefore it is important to examine the performance of the technologies applied in LTE-Advanced system. In this paper, we analyze the performances of the transmission modes in the downlink spatial channel model of LTE-Advanced system.